Field of Invention
The present invention relates to camera modules, and more particularly to a camera module and array camera module based on an integral packaging technology.
Description of Related Arts
A camera module is one of the indispensable components of an intelligent electronic device such as smart phone, camera, computer device, wearable device, and the like. With the continuous development of a variety of intelligent devices and the popularity of the intelligent devices, the camera module requirements are getting higher and higher.
In recent years, intelligent electronic devices have been developed by leaps and bounds, the growing trend of the intelligent electronic devices is towards thinner and thinner. In order to adapt such development, the camera module of the intelligent electronic device is required to be multi-functional, lightweight and compact in size, so that electronic equipment can be made thinner and thinner while meeting its imaging requirements. Therefore, the camera module manufacturers continue to focus on designing and manufacturing camera modules that meet these requirements.
Molded packaging technology is an emerging packaging technology developed from the conventional COB (Chip on Board) packaging technology. As shown in FIG. 1A of the drawings, a circuit board encapsulated by a conventional integrated packaging technology is illustrated, wherein a packaging portion 1 is packaged on a circuit board 2 through a packaging process, and then a chip 3 (such as an imaging sensor and a photosensitive element) is connected to the circuit board 2, and a light filter 4 is installed to the molded portion 1. The packaging portion 1 embeds the electronic components 5 which are provided on the circuit board 2, so as to reduce the occupying space for the electronic components 5 of the camera module, so that the size of the camera module can be made smaller and it can also solve the problem of the dust that may adhere on the electronic components 5 and adversely influence the imaging quality of the camera module.
As shown in FIG. 1B, a circuit board packaged through a conventional COB technology is illustrated. In comparison with the conventional COB packaging technology, the packaging technology has many advantages. For example, through replacing the holder 7 with the packaging portion 1, the occupying space for the electronic components 5 can be reduced so as to reduce the size of the camera module, and that the dust that may adhere on the electronic components 5 and adversely influence the imaging quality of the camera module can thus be avoided. However, some new problems arise in such conventional packaging structure.
The light filter, which is a very important component in a modern camera module, serves to filter infrared lights, so that a desired light observing performance similar to a human eye observing effect can be achieved. The light filter is easy to be damaged. It also plays a significant role in the manufacturing cost of the camera module. The larger the size of the light filter, the more expensive of the light filter. In addition, when the filtering area of the light filter is relatively large, the degree of the manufacturing accuracy of the light filter is relatively hard to control too. Therefore, the issue of the light filter should be carefully considered when adopting the packaging technology.
First of all, in comparison with the conventional COB packaging technology, the packaging portion embeds the electronic components 5 in the packaging technology so as to further utilize the space and position of the electronic components 5. However, comparing with the COB holder as shown in FIG. 1B, the introduction of the packaging portion must increase the assembly space of the light filter 4 at top of the packaging portion. In other words, a relative larger size of the light filter 4 is required for the packaging technology.
More specifically, referring to FIG. 1B, the light filter 7 as illustrated is installed on the holder 7 in the conventional COB technology. Because the holder 7 is installed on the circuit board 2 in a later step, it can be manufactured to have different shapes. For example, as long as the photosensitive area is not blocked, the holder can extend inwardly to reduce the size of the light filter as much as possible, so as to enable an easy assembly while ensuring to fulfill its utility requirement. And, since the light filter with a relatively smaller size can be used, the manufacturing cost of the camera module can be reduced. However, in the packaging technology, the packaging portion 1, which is integrally formed on the circuit board 2 through a set of moulds, is integrally extended from bottom to top, so that the size of the light filter 4 is determined by an opening of the packaging portion 1, and thus the light filter is inevitable to be relatively large.
Secondly, in the packaging technology, as shown in FIG. 1A, the light filter 4 is required to be installed in a groove 6 of the packaging portion 1. However, because of the adoption of the packaging technology, the shape of the corner of the groove 6 is hard to control. In other words, the groove walls for forming the groove 6, especially the joint position between the adjacent groove walls, are prone to deform that, for example, may produce some blurs so that it is not able to provide a good assembling condition for the light filter 4, and thus smoothness is hard to guarantee. The light filter is also easy to get damages. However, in a conventional holder 7, an inner groove 8 can be provided. In other words, the holder 7 can extend inwardly to provide a sheltering position for the light filter 4 while reduce the assembly area of the light filter 4. However, since the packaging portion is formed through an integrally forming process, a demoulding issue exists in the manufacturing process, so that the structure of the conventional holder can be manufactured by the packaging process. Therefore, the conventional packaging technology can only provide a limited structure, e.g. the packaging portion 1 without the inner groove 8. The conventional holder, the packaging holder, and their forming processes both have their own advantages and disadvantages. Therefore, a combination of the advantages of the two structures is desired.
Thirdly, even the packaging portion 1 is constructed to be a flat step structure without the groove 6, it ensures that the surface of the packaging portion 1 has a good flatness for providing a good assembly condition for the light filter 4. However, in this structure, on one hand, the light filter 4 has to share the packaging portion 1 with other components such as a lens or an actuator, so that a relatively high requirement for the assembly accuracy is required, or otherwise these components may damage the light filter during the assembly process. On the other hand, a distance between the light filter and the lens is relatively small, so that a lens element of the lens may easy to have contact with the light filter, and also a back focus length of the lens is increased.
Furthermore, the circuit board is required to be installed with the photosensitive element, the electronic components, and the packaging portion, so that the layout of these components will have an influence on the area of the circuit board. Because of the integral forming manner of the molded portion, the area of the packaging portion will be larger than the area of the conventional holder, i.e. the occupying area of the packaging portion on the circuit board is relatively large.